One of the most common ornaments in traditional harp music, the triplet, is also one of the most troublesome!
The triplet (also known as the treble) is a series of three repeated notes . They can be decorative, but primarily serve a rhythmic purpose. There are various possible fingerings - 432, 321, 212 etc are all possible, and the choice will depend on the tune and what direction your fingers need to go in before and after the triplet.
One of the most common problems I hear with triplets is that not all three notes sound equally. Often one note ‘sticks out’ or a note is ‘lost’ so rather than hearing three crisp notes, the triplet becomes lumpy.
A simple way to counteract this is to practice accenting different parts of the triplet. This will require you to really tune your focus into what each individual finger is doing, and check that each note is really sounding.
Try playing these three variations (can be with any fingering) to see if all your fingers are equally strong!